Growing Under Cover

Colin Gore was building a small greenhouse of his own, an interest spawned by a passion for cooking and an appreciation for fresh, quality ingredients. Growing his own food – in his own greenhouse – also appealed to his interest in conserving energy, and helping reduce the cost and energy use that the retail and wholesale produce industries require to transport and process product.

Linvilla Orchards Garden Center and Greenhouse from the yard.PHOTO COURTESY OF LINVILLA ORCHARDS.

“I have a strong, almost manic, drive to create foods from scratch with an interest in improving their quality,” he says. “Growing my own food was an extension of that drive. Building a greenhouse was a step to further improve my crops.”

Though he was still a student at Lehigh University at the time, Gore started planning a 4-by-8-foot greenhouse at his off-campus residence during the fall of 2007. “I’d heard that some of my favorite veggies, collard greens and Swiss chard, were hardy enough to grow year-round in a greenhouse in Bethlehem [Pa.],” he says. “I didn’t know a lick about building a greenhouse, though.”

Research netted a wealth of books and scholarly papers about greenhouse design, especially from the 1970s onward. The turning point was discovering Alward and Shapiro’s Low-Cost Passive Solar Greenhouses. Using simple materials, they optimized greenhouse structures to waste as little of the sun’s energy as possible. The term “passive solar” describes their lack of moving parts or external power sources – and they are ultra-efficient and don’t require additional heaters like the glass-box style greenhouses do.

“The intriguing part of the design is that there isn’t a copy-and-paste solution,” Gore says. “Measurements had to be adjusted depending on your climate and latitude. I’m fond of the notion that we must design with location in mind. Passive solar design really makes that point visceral.”

Whatever the size or number, all growers want to get the best from their greenhouses, whether a new or a retrofit model(s); all growers need a greenhouse to benefit their operation.

As for Gore’s initial design, the angle of the sunlight gathering window, the glazing, needs to match the angle of the sun during the coldest part of the year to help the greenhouse absorb the most sunlight when it most needs heat. The other main considerations were adequately insulating and sealing the structure. A final touch was using water barrels to absorb heat during the day, keeping the plants from overheating, and then releasing heat at night.

No surprise, Gore is now a graduate research assistant in a doctoral program at the University of Maryland, and his research group founded the university’s Energy Research Center. He’s pursuing a career in sustainable energy generation, and currently focused on developing solid-oxide fuel cells to convert existing fossil fuels into usable energy more efficiently than traditional combustion engines – all good genetic blueprint material for applying to greenhouses and growing operations.

Green House’s greenhouse

After designing and fabricating his portable 4-by-8 greenhouse from scrap 2x4s, plywood and plastic sheeting, Gore’s expertise was tapped at Lehigh. He led a seminar on greenhouse building before summer break in 2008 at Green House, the campus’ evolving environmental residence hall that’s geared toward sustainable living. After an internship in Graz, Austria, a Lehigh friend, Alice Kodama, had not only secured permission to build a greenhouse next to Green House, but Residential Services agreed to fund the project.

Original CAD file sketching out greenhouse dimensions and materials.PHOTO BY COLIN GORE.

It arrived just in time. While in Austria, his first greenhouse had been hacked open by landlords on police orders and was beyond repair. “I suppose they assumed that a college student with a greenhouse in a South Bethlehem backyard was probably growing pot,” Gore says. “What they found was a bunch of beets and radishes.”

Though Gore was not a Green House resident, he designed what its denizens call the “solar shed” his senior year. It was dubbed the “solar shed” to avoid confusion with the Green House. Gore planned a 16-by-8-foot footprint. Since having a perfectly sealed structure relies on frame construction, the students hired a contractor to lay a foundation and take charge of most of the building.

Inside, all exposed wood is sealed to prevent moisture damage and painted white to reflect sunlight back toward the plant benches.PHOTO BY ALICE KODAMA.

For his first greenhouse, a few dozen water-filled milk jugs were adequate for providing the needed heat storage. For the solar shed, a tip led to donated rain barrels, first from a local car wash. Eventually, students gathered 10 55-gallon drums.

The solar shed was complete in February of 2009, just in time to get seedlings started for a spring crop. They contacted local seed vendors for seed or soil donations, and Rodale Institute asked some of its suppliers to donate as well.

“I’m a bit fuzzy on what our first crop was, but I know there was some flats of arugula, a few kinds of lettuce and some tomatoes,” says Gore, who along with Kodama have remained solar shed consultants for current Green House residents. “Since most students are not in Bethlehem during the summer, the greenhouse allows them to start a growing season in late winter and have crops before the semester is over. It’s quite a unique botanical opportunity for the itinerant student.”

Bigger and better

Not far from Lehigh, Dan Schantz Greenhouse has recently doubled in size to 42 acres of greenhouse space in four wholesale locations and two retail outlets in Pennsylvania and Maryland. The key to growth has been good credit and sales. “You can’t build a greenhouse without sales,” says Paul Hardiman, head grower at Dan Schantz Greenhouse.

Initially Schantz and his wife Mildred’s main crops were fruits and vegetables when they built their first 22-by-100-foot greenhouse in 1961. Today, 3 percent of the annual product – about 3,000 flats – is vegetables, and the rest is flowers. For the fall, Schantz grows over 900 acres of fall ornamentals at multiple sites. It operates a year-round growing schedule.

Other than size, what’s most impressive is the effort to continue to experiment and improve plant health and worker safety. In the last one and a half years, Hardiman has expanded biocontrols in the greenhouses. Currently, about an acre’s worth of the vast greenhouse empire is in biocontrol – mums, some herbs and strawberries, mostly to combat spider mites, thrips and aphids. Though initially skeptical, and despite changing providers to Biobest after a slow start this spring, it’s a move that looks promising. Ladybugs, voracious predators, are welcome, as is a greenhouse population of parasitic wasps.

After a reinoculation in mid-May, there were no problems and plants were popping and growing without sprays, so there’s also less worry that spraying would somehow impact the safety of its workforce. Biocontrol costs have been on par with spraying. Now, while establishing needed predator populations, the hope is that in five years they’re not spraying at all.

With biocontrols, Hardiman says you have to be more observant, and “scout and look for more.” With spraying, “the idea is to kill everything.” There’s no additional staff, though some already have some entomology experience. “We don’t just look at the pretty stuff, but rather the stuff that doesn’t look right,” he says.

The bottom line is that plants will have a better shelf life without chemicals, and sales can continue soaring. “We can’t back that up yet,” Hardiman says. “It’s just what we hear. If we try to do better and fail, [Schantz] is OK with that, as long as we’re not lazy with what we do.”

In a separate greenhouse experimentation this spring, Hardiman is working on lowering nitrogen levels by 50 percent without affecting plant quality. “But you can’t take the shortcut and not get the results,” he warns.

Dan Schantz Greenhouse, which employs 350 people in-season, has 8 acres of open-roof glass greenhouses, the bulk of which are in Maryland. They’re the best kind, Hardiman says, because plants don’t get as stressed as in a double-poly plastic structure, and glass allows better light transmission. Glass also allows a grower to cheat at night and not run heat (or fans for cooling) because the glass keeps a more even-keel temperature all day. “It’s the way to go if you have a lot of cash,” he says.

Otherwise, the company operates ultra modern greenhouses, with Argus computerized controlled environmental systems since 1996, floor-flooded watering and bulb coolers with a capacity of holding over 4 million bulbs.

While large, Hardiman argues that the smaller greenhouse operation you are, the more reason there is to “bite the bullet with expenses.” Small growers are probably driving the delivery truck, too, or making sales, so while away from the greenhouse an environmental control system can alert the grower of a problem. Networked systems can be accessed from an office computer. There’s flexibility, as well, since you can define your parameters.

Up from the ashes

After an August 2002 fire destroyed its landmark octagonal barn, the Linvill family promptly rebounded by rebuilding in time for their prominent fall season that same year. Since then, it has added a garden center with greenhouses to its already prosperous 300-acre farm and business, Linvilla Orchards in Media, Pa.

Groundbreaking for the 15,000-square-foot center, which was designed by Media’s Baggot & Bak, was in November 2009, and Nexus Greenhouses was the contractor. The grand opening was last fall.

An environmentally friendly operation, there’s a geothermal pump to provide winter warmth and coolness in summer. The polycarbonate greenhouse roof provides greater insulation, and opens vertically to control ventilation and summer heat escape. Controlled by a computer, it senses rain and wind, and can withstand 3 feet of snow. The greenhouse shade curtains are also computerized to close automatically, blocking out 50 percent of sunlight. They close incrementally at night to conserve heat. Duct work is of cloth, not metal, which eliminates condensation. Rainwater is collected in a cistern and used to water plants, and the stamped concrete floor’s radiant heat comes from water heated by a wood chip burner/boiler.

The author has been published in national and regional magazines as well as daily and weekly alternative city newspapers. A gentleman farmer in Quakertown, Pa., he writes about people, social trends, historic preservation and 18th century America, agrarian culture, land use and sports and recreation topics.

About the AuthorJ.F. Pirro

J.F. Pirro is a gentleman farmer in Quakertown, Pennsylvania. He writes about people, social trends, historic preservation and 18-century America, agrarian culture, land use, and sports and recreation topics.